A Liquid Crystal Display (LCD) has been widely applied to a display field.
It is well known that a black matrix itself is not charged. However, during a normal operating process of the LCD, the black matrix may induce a charge, and therefore, the black matrix has a certain voltage value, to maintain a balance of an in-cell electric field. Meanwhile during production and subsequent transport and evaluation processes of the LCD, due to equipment and personnel, static electricity may be accumulated on a color filter substrate, and the static electricity enables an inductive potential on the black matrix to be unbalanced in distribution, and then deflection of liquid crystal is influenced, thereby influencing a display effect of the LCD finally.
Therefore, detecting a voltage value of the black matrix may effectively reflect a static electricity accumulation degree of the color filter substrate, and then a data support is provided for subsequently removing the static electricity on the color filter substrate. An existing method for measuring a voltage of the black matrix is to open glass at one corner of the LCD, so as to expose a film layer of the color filter substrate, then, scrape off a planarization layer on the color filter substrate to expose the black matrix, and subsequently coat the exposed black matrix with a silver paste and then perform voltage measurement. After the voltage of the black matrix is measured through the above-described method, the LCD has been already damaged, and cannot be used any longer subsequently. For a manufacturer, it is a great waste.